I need to make a swith send a pulsing signle. Low voltage for a video
game constoller. Can this be done with resistors or diodes? Whould thay
have something like this at radio shack?
Depends on what you're comfortable with. One way would be a monostable
where the rising edge of the pulse triggers an astable. This could be
built out of discrete components or 555 timers (all available at Radio
Shack). If you don't want a delay (as in how computer keyboards normally
have a small delay before they start to auto-repeat) then a single
astable oscillator (again, discretes or a 555 timer) would do the trick.
Another approach would be a little 8-pin microcontroller with an
internal RC oscillator, so no crystal or external clock would be needed,
just power, ground, signal in, signal out. Might even be cheaper than
doing it with discretes. Radio Shack doesn't carry single
microcontrollers and what they do have (Basic Stamp) is overkill for
this. An ATtiny13 at about $1.40 qty one (Digikey) would be dead simple
to program for this.
You could fancy-up either approach with an enable switch, variable
delay, variable firing rate, indicator LEDs, sound, ...